Monday, April 5, 2010

Carving a Rose

My tool kit for rose carving is pretty simple.

Frequent honing is important, so my 8000 grit ceramic stone is close by. To outline the borders of the rose I use an inexpensive Olfa compass cutter. I find this tool gets the job done, but there's more flex and play in it than I'd prefer. One day I'll make a more substantial tool. To cut through the soundboard I use two home-made punches, 1.5 and 2 mm. These started life as high speed steel drill bits which I ground down and fixed in wood handles. The 1.5mm is wrapped in cushioned grip tape which makes it easy to hold and prevents wrist strain. I have a Japanese skew chisel for the chip carving used in borders, and a Veritas Carving knife. I hesitated before buying this as it's a bit expensive but I've found it far superior to the X-acto handles. It's loaded with a #11 surgical scalpel blade.

A close-up shot. The cutting mat is an important part of the set-up too. I've screwed mine to a piece of plywood that I can carry around the most comfortable location I can find. Comfort is necessary due to the amount of body control required. I try not to work longer than an hour at a time on this stuff in order to prevent cramping and loss of dexterity. It's engrossing though, and time goes by pretty fast due to the focused nature of the work.

Here's a rose pattern I designed for my current batch of four 7 course lutes. I laid it out on 1mm graph paper and colored in the negative space. On one side I sketched in the over/under cuts to get a better look at what the weaving effect would do. It's glued in place on the inside of the lute.

Photocopying the pattern can distort things a bit, as can the uptake of moisture from the glue, as can the stretching effect of pressing it in place on the sound board. I suppose the smart thing to do would be to make up a CAD pattern and take it to a laser cutter. But where's the fun (and eyestrain) in that?! Seriously though. What's the point in making a lute at all, when a computer generated midi synth can do the playing for you? In the words of Cosmo Kramer, "Why fly a kite when you can just...pop a pill? Ee-yayuh!"

The scalpel is used to initiate the outline of the cuts. Its most important function is to provide a little compressed area for wood to move into when the piercing cuts take place. Think of digging in clay with a flat spade. Because of the linear nature of the grain , if any pressure is placed against an unsupported segment the connective structure will fail and (pop!) out breaks a little sliver. Then I've got to glue it back in place. Bother.

I was surprised to hear Grant Tomlinson describe his technique as "punching out a rose". It's an accurate description though. The cutting takes place by chopping down vertically with the tiny chisel which is beveled at an extremely low angle, probably 10 degrees or so. Care must still be taken to provide relief cuts and to respect the grain direction. Just a note on scale, I used the macro function on the camera -these little squares are only 2mm wide.

Eventually all sides are loosened and the chip pops free. By keeping the cuts vertical, there's little deviation in the pattern when I turn it over to complete the visible side. I use the scalpel to clean up any fuzzy cuts. I then use the skew chisel to make the over and under pattern, cutting half way (1/2 mm) through the thickness of the board. The back side of the rose is bolstered with a number of 2mm square spruce splints as well as a portion of the bracing structure. I dye these supports black to make them less visible.The surface of the rose is painted with a thin spirit varnish to seal things up a little bit.

Here's a finished rose of the classic "Knot of Leonardo" variety. The pattern came from Lundberg's Historical Lute Construction. I can pick out the problematical areas, and it's not quite as crisp as the laser would cut. I'm still proud of it though. I recall bringing in one of my early efforts to work. One of my co-workers was a proficient carver of decoys, caricatures and the like. "You're nuts", he said. He's perfectly right of course. Few other crafts push the limits of wood as a structural medium to such outlandish extremes.

I very much appreciate your post. I live in Hamilton since this Spring and hope to start building my first lute soon. Next time you do it in your shop I would very much appreciate the opportunity of observing it. I hope this doesn't sound outlandish. I play classical guitar and lute. Regards, Kadmos